NEETPhysicsNuclear Physics
Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A): The nuclear density of a heavy nucleus like ²³⁸ U is approximately the same as that of a light nucleus like ⁴ He . Reason (R): The nuclear force is short-ranged and exhibits the property of saturation, meaning a nucleon interacts only with its nearest neighbours. In the light of the above statement
Options
- ABoth (A) and (R) are true and (R) is the correct explanation of (A)
- BBoth (A) and (R) are true but (R) is not the correct explanation of (A)
- C(A) is true but (R) is false
- D(A) is false but (R) is true
Correct answer
A. Both (A) and (R) are true and (R) is the correct explanation of (A)
Step-by-step solution
The nuclear density is independent of the mass number A , meaning all nuclei, whether light like ⁴ He or heavy like ²³⁸ U , have approximately the same nuclear density. Thus, the Assertion is true. The constancy of nuclear density is a direct consequence of the saturation of nuclear forces. Because the nuclear force is short-ranged, a nucleon only interacts with its nearest neighbours rather than all nucleons in the nucleus. This saturation prevents the nucleus from collapsing into a denser state as more nucleons a